Feeding, gauging and sorting means for metal sheets



March 12, 1963 G. H. BENDIX ETAL 3,080,967

FEEDING, GAUGING AND SORTING mus FOR METAL SHEETS Filed Sept. 12, 1958 1 s Sheets-Sheet 1 l6 l6 3 I I 'l I q I N l9" '1 5' I9 I v i 5 5 22 I ll? lg! an 5 I! i I L1I. -p-H-ll4ll| i i m 20 E 3| Ilhl I 5 i i Z I k i 5 I5 I? FIG. I.

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FEEDING, swarms AND SORTING'MEANS FOR METAL SHEETS Filed Sept. 12, 1958 I w 4 I A V I 1A INVENTORS wflaw W ATTORNEYS a h 1963 s. H. BENDIX ETA]. 3, 7

FEEDING,. GAUGING AND SORTING MEANS FOR METAL SHEETS.

Filed Sept. 12, 1958 5 Sheets-Sheet 3 FIG. 5.

INVENTORS ATTORNEY J March 12, 1963 G. H. BENDIX ETAL FEEDING, GAUGING AND SORTING MEANS FOR METAL SHEETS Filed Sept. 12, 1958 5 Sheets-Sheet 4 FIG.

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INVENTORS ATTORNEY March 1963 a. H. BENDIX ETAL 3,

FEEDING, GAUGING AND SORTING MEANS FOR METAL SHEETS Filed Sept. 12, 1958 5 Sheets-Sheet 5 FIG. 9.

INVENTOR M All! #ZW ATTORNEYS l United States Patent 3,080,967 FEEDING, GAUGING AND SORTING MEANS FOR METAL SHEETS Gordon H, Bendix, Orland Park, and Richard F. Tamrn, Elmhurst, Ill., assignors to Continental Can Company, Inc., New York, N.Y., a corporation of New York Filed Sept. 12, 1958, Ser. No. 760,802 4 Claims. (Cl. 209-82) The following specification relates to combined feeding, gauging and sorting means for ferrous metal sheets. Ferrous metal sheets, for example tin plate, are supplied by the manufacturer cut into rectangular sheets which are stacked in piles. As received from the mill, these sheets must be separated and fed to machines which will cut up the individual sheets into the desired shapes for subsequent fabrication.

While the individual sheets are generally uniform in thickness Within a certain range, still variations occur which require that the sheets be sorted according to thickness. Any sheets that are either too thin or too thick to meet the requirements of thefabricated article to be subsequently produced should therefore be diverted from the fabricating machines. Such diverted sheets are then either scrapped or else used in the fabrication of other articles in which the thin or thick sheets may be used advantageously.

It is therefore important that some means he provided which will register the thickness of each individual sheet asit is fed and either advance it for subsequent operations or in the alternative divert the sheet according to its abnormal thickness. We have combined with the usual automatic sheet feeder, means for simultaneously determining the relative thickness of each individual sheet and thereafter routing it in accordance with such thickness for appropriate use.

One of the objects of this invention is to combine a sensitive thickness gauging head with a well known type of automatic sheet feeder.

It is a further object of our invention to provide a suitable adjustment for the gauging head so that it will at all times operate satisfactorily on the individual sheets as they are picked up from the pile.

A further object of the invention is to use the gauging head as a means for directing the sheet as it leaves the feeder into any one of a number of paths determined by the relative thickness of the sheet.

Other objects of the invention will be apparent from the following description of the preferred form as illustrated in the accompanying drawings on which:

FIGURE 1 is an end elevation a sheet feeding mechanism equipped for combined feeding and gauging metal sheets;

FIGURE 2 is a similar view showing a sheet in the feeding and gauging position;

FIGURE 3 is a perspective view of the gauging head and mounting;

FIGURE 4 is a central vertical section of the head;

FIGURE 5 is a side elevation of the sheet feeder frame and parts operatively dependent on the gauging head;

FIGURE 6 is an enlarged side elevation of the reject solenoids in FIG. 5 and the related diverting fingers;

FIGURE 7 is a side elevation partly in vertical section taken on the line 7--7 of FIG. 8 of a switch mechanism;

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FIGURE 8 is a fragmentary front elevation of the mechanism of FIGURE 7, and;

FIGURE 9 is a diagram of the electric circuits used.

Briefly considered the invention consists in assembling an automatic sheet feeder with a sensitive electromagnetically operated gauging head and With means responsive to the thickness indication of said head for directing the sheets as they are fed individually into any one of a number of appropriate paths.

We have shown the invention as applied to a well known type of automatic sheet feeder known as the Dexter feeder. As this sheet feeder is well known and of wide use, the illustration and description of it has been limited to those parts which are utilized in the gauging and sorting operations.

This type of automatic sheet feeder makes use'of a crossbar 11. Below the crossbar and approaching it vertically is an elevating platform 12 upon which a pile of tin plate or other ferrous metal sheets 13 are raised into position to be acted upon by the feeder. The extent of elevation is controlled by means of the customary feeler 14 mounted at the middle of the crossbar 11. This feeler is suspended in an adjusted position so that when the pile of sheets is depleted and contact is lost by the feeler, the elevating mechanism is actuated and raises the top level of the pile into contact with the feeler.

The platform 12 is elevated by cables 15, 15 running over pulleys 16, 16.

The pile of the sheets is held with the rear edges of the individual sheets in vertical alignment. This is done by a pair of curbs 17, 17, also suspended from the crossbar 11.

As each sheet is individually lifted from its position at the top of the pile, a jet of compressed air is introduced below the sheets from a manifold 18 suspended from the crossbar 11. This jet of air supplements the usual lifting movement and frees the top sheet 21 from its frictional contact with the lower sheets. At the sametime the jet of air serves to counterbalance the resistance of the atmosphere through which the sheet 21 is being lifted. As an alternative the sheets may be separated magnetically or a combination of an air jet and magnetic separation may be used.

The lifting means for the sheets comprises a pair of vacuum operated cylinders 19, 19. These cylinders are mounted vertically on the crossbar 11, one near each corner of the pile of sheets. The cylinders 19 have depending pistons 20 armed with vacuum cups. The pistons are hollow and thus serve to apply vacuum through the cups when in contact with the top sheet 21. The pistons 20 with their vacuum cups are dropped periodically by vacuum operated cylinders 19 and connected vacuum tubes 97 into contact with the top sheet 21 and thereafter the application of vacuum serves to fasten the cups to the sheet and lift it as the pistons rise due to the blockage of air entrance through the cups by the sheet. In FIGURE 1, the pistons have been shown in the downward movement and before making contact between the vacuum cups and the upper sheet. FIGURE 2 illustrates the upward retraction of the pistons lifting the rear corners of the top sheet 21. Due to the resilience of the sheet metal and its weight, it takes an undulating position with its free ends at variable angles with the horizontal.

A gauging head 31 for the elevated sheet is provided in fixed position at one end of the crossbar 11. The crossbar carries a vertical standard 22 fixed upon the crossbar. This standard has a vertical slot 23, shown in FIGURE 3.

An angular bracket 24 is provided with a vertical slot 25, 25 in each flange. Either flange may be placed in contact with a side of the standard 22 with one of the slots 25 in registry with the slot 23 on the standard. A bolt 26 passing through the slots will permit vertical adjustment of the bracket relative to the standard.

Each flange of the bracket 24 is provided with an arcuate slot 27. Where the slot intersects the slot 23 of the standard, a bolt 28 may be fastened. In this way the bracket 24 may be given any desired angular position by rocking the attached flange around bolt 26 as a pivot and fastened into the adjusted position by means of the bolt 28.

A stirrup 29 is formed as an angular piece of metal. A bolt 36 passing through the vertical portion of the stirrup is used to clamp the stirrup to the free flange of the bracket 24.

An electromagnetic gauging head 31 is fastened to the underside of the horizontal portion of the stirrup 29 as shown in FIGURE 3.

The gauging head consists of a two-compartment housing, shown in FIGURE 4. The lower compartment 32 has an annular opening in its bottom surface 33. A magnetic core 34 depends through the lower compartment and in the plane of the bottom 33.

An upper compartment 37 has a horizontal partition 35. Wires 36 and 43 pass through the partition 35 and into the lower compartment.

An opening 39 for vacuum tube 96 enters the top of the upper compartment but is in communication with the lower chamber 32 through holes 35' in partition 35. Vacuum is thus also provided in the lower compartment 32 and forms a suction across the bottom 33.

A coil 40 is fixedly mounted within the lower compartment 32 and slightly spaced above the bottom 33. The coil surrounds the core 34 within which a magnetic flux is developed when the coil is energized.

The gauging head 31 thus described is disclosed in our copending application filed September 10, 1953, Serial No. 379,434 now Patent No. 2,935,680 dated May 3, 1960.

A conduit 44 best shown in FIGURE carries the wires 36 and 43 from the head 31 to a panel board 45 mounted on the fixed frame 46 of the automatic feeder. A conduit 47 carries wires (not shown) to reject solenoids 48 and 48' also mounted on the frame.

As shown in FIGURE 6 the armature 49 of solenoid 43 has a spring link 50 loosely fitted over a pin 51 on a crank 52 whose other end is pivotally mounted on shaft 53. This shaft is fixedly mounted on the frame. The link 50 has lost motion so that the crank 52 may be rocked independently of the link.

On a rock-shaft 54 pivoted on the frame of the feeder beneath the path of the sheets as they are fed forward, in the direction of the arrow in FIG. 6 by the usual forwarders and drop rollers of the well known feeder is a series of fixed parallel fingers 55. A rock arm 56 is fixed on the shaft 54. A latch bar 57 extends upwardly from the arm 56 and rests against a cam follower 41 mounted on pin 51 of the crank 52. A spring 42 biases latch bar 57 towards the cam follower.

The upper end of the latch bar 57 is notched as shown at 58 in FIGURE 6. The upper end of the latch bar 57 projects through a slot in an oscillating arm 59. This arm is pivoted on the frame (not shown) and is lifted once in every cycle of feeding by suitable linkage or cam operated by the feeder as the tested sheet is advanced over the fingers 55.

Endless ribbon belts (not shown) advance the sheets in the usual sheet feeding manner in the direction indicated by the arrow on FIG. 6, over the fingers 55.

Opposite the end of fingers when in lowermost position, is a conveyor upon which the tested sheet is delivered if it is of normal thickness within a predetermined tolerance.

When however the variance is too great due to excess thickness, the reject solenoid 48, draws the crank 52 to the left, thus engaging notch 58 in the latch bar 57 with the end of the oscillating arm 59. The latter lifts the bar 57 and the arm 56 lifting the fingers 55.

As a result the over-thick sheet is diverted from conveyor 60 and delivered to an upper tray 61.

After the over-thick sheet has been deposited on the tray oscillating arm 59 lowers the fingers 55 to the lowermost position.

The circuit through the reject solenoid 48 is then broken, the bar 57 moves to the right under the influence of the spring 42 and comes to rest against stop 62. The latch bar is thus released from the arm 59 and the fingers 55 come to rest on a stop beneath the fingers. The next sheet, if of normal thickness, will then be fed to conveyor 60.

I A second reject solenoid 48' similar to '48 is also mounted on the frame in the same operative relation to a second crank 52 similar to 52. Crank 52 is also pivotally mounted on stationary shaft 53. The second reject solenoid is arranged to be energized by current when a sheet of less than permissible thickness is indicated by the test head. Thus the second crank 52 may engage a second latch bar 57 with the oscillating arm 59. In such case the size of the notch 58' in latch bar 57' will give a greater lift to the latch bar 57' and result in the fingers 55 being raised to a higher level. They thus divert the thin sheet to a second and highest tray 63.

From the panel board 45 there is a conduit 64 by which a circuit is brought to a timer 65 shown in FIG- URES 7 and 8. The timer is driven by a rotary drive shaft 66 operated in synchronism with the sheets being fed. This drive shaft in turn is geared to a pair of interconnected gears 67, 68.

Within the housing of the timer 65 the shafts 67 and 68 of gears 67 and 68 carry cams 69 and 70 respectively. These cams serve to operate timing switches 71, 72, respectively.

The positions of the timing switches are set so that they will serve the purpose of timing the operation of the solenoids 48 and 48'.

Power for the gauging and sorting operation is supplied in the following manner.

Incoming single phase 110 AC. current is supplied through leads 73, 74 as shown in FIGURE 9. Current is drawn from these leads at terminals 75, 76 by the relay circuits through 75' and 76 for operating the sorting mechanism.

Current from the line leads 73, 74 passes through the primary coil of a constant voltage transformer 77. Output current from transformer 77 is delivered from terminals 78 and 79 to the primary of transformers 80 and 81 supplying bias voltage to thyratron tubes 87 and 90.

Current from terminals 78, 79 also is passed through a coil 82 inductively related to a reference sheet of metal or tin plate 83 having a thickness less than the thinnest sheet that would ever be supplied to the sorting device.

The individual sheets 21 are also inductively related to the coil 40 in the test head 31. The coils 40 and 82 therefore form parts of an electrical bridge by which the sheet 21 is compared with the reference sheet 83.

The rectified output of transformer 84 is in series opposing with the rectified output of the secondary circuit of transformer 80. The amount of the voltage taken from transformer 80 is subject to control through the variable resistance 85. The resulting voltage is transmitted to the grid of tube 87 by wire 86.

. The rectified output of transformer 88 is in seriesopposing. with the rectified output of the secondary circuit of transformer 81. The amount of thevoltage taken from transformer 81 is subject to control through the variable resistance 89. The resulting voltage is transmitted to the grid of .tube 90 by wire 87.

The output from tube '87 passes through the coil of relay 91. This relay is energizedby the current from terminals 75, 76. Timing switch 72 is interposed in the circuit from the terminal 75 to the relay 91. i

The current output from tube 90 is delivered to the coil 'of relay; This relay is also connected through the lead 93 to the timing switch 72 and the current supply 75.

If the magnetic and inductive characteristics of coil 40 balance those of the coil 82 related to the reference 83, no current will flow in the branches leading to the transformers 84 and 88. When, however, sheet 21 has a greater thickness than the reference sheet 83 but is less than the desired normal thickness, current will flow to the transformers 84 and 88. Voltage from the adjusted variable resistance 85 together with the rectified secondary voltage of transformer 84 is such that the resulting voltage in wire 86 connected to the grid in tube 87 Will be insufficient to make the tube conduct, therefore current will not pass through the coil of relay 91. Since the coil of relay 91 is not activated and since the contacts of relay 91 are normally closed, a circuit is formed from terminal 75' through the timing switch 71, when it is closed, through wire 95, the closed contacts of relay 91, through the thin reject solenoid 48 and out through terminal 76'. This causes the solenoid 48' to pull its armature 49 inwardly thus rotating the arm 52' to cause the latch bar 57 to be moved to engageable position with the oscillating arm 59. Thus when the arm 59 begins its upward movement it will engage the notched-out portion 58' in latch bar 57. Latch bar 57 will be lifted until the fingers 55 are in position to feed the thin sheet on to the tray 63. After the sheet has been deposited on the tray the fingers 55 will be lowered to their lowermost position. Timing switch 71 next'opens, breaking the cir-' cuit to the thin reject solenoid and the spring 42 retracts the latch bar 57 out of engagement with the arm 59. Timing switch 72 then opens to break the circuit through the coil of relay 91 which in the case of a light sheet is unnecessary as this circuit it not energized. When a sheet of normal thickness is lifted by the cups 20 into contact with the gauge 31, sufiicient voltage is set up in wire 86 to fire the tube 87 causing the coil in relay 91 to beenergized, by current passing from terminal 75 through the closed timing switch 72, through the coil of relay 91 and then to terminal 76' through the tube 87. The normally closed contacts of relay 91 are thus opened and thus the thin reject solenoid 48' will not be energized and the latch bar 57' will not be drawn into engageable position with the oscillating arm 59 and the fingers 55 will remain in their lowermost position and thus direct the normal sheet on to the take-away conveyor 60'.

If a sheet of greater than normal thickness is fed sufficient voltage will be developed in wire 86 connected to the grid of tube 87 to cause the contacts of relay 91 to be opened and thus cause the thin reject solenoid 48 to be de-energized in the same manner as when a normal sheet is fed. However, the thicker than normal sheet will cause a sufficient voltage to be induced in the secondary of transformer 88 to overcome the opposed polarity biasing voltage in the variable resistance 89 resulting in a sufficiently high voltage in wire 87 connected to the grid of valve tube 90 to cause the tube to fire thus setting up a circuit from terminal 75 through the closed timing switch 72, through wire 93, through the coil of relay 92, through the tube 90, and back to terminal 76. The current through the coil of relay 92 causes the normally open contacts of the relay to be closed. A circuit is thus completed from terminal 75 through the closed timing switch 71, through the contacts of relay 6 92 and then through the thick reject solenoid 48 and back to terminal 76. This energizes solenoid 48 causing it to draw in its armature 49 thus moving the arm 57 into engageable position with the oscillating arm 59 so that when the arm 59 rises in its timed movement, it

will engage the notched out portion 58 in the latch bar' 57, causing the latch bar 57 to be raised until the fingers 55 are in position to direct the heavier than normal sheet on to the tray 61. After the sheet has been delivered on to the tray the arm 59 goes down to its lowermost position, thus lowering the fingers 55 to the lowermost position. The timing switch 71 then opens to de-energize the thick reject solenoid 48, and timing switch 72 opens to de-energize the coil of relay 92 causing the relay contact points to open. The current flowing through the relay coil 92 is maintained even after the sheet being fed is disengaged from the detecting head causing the voltage in Wire 87 to drop below the required voltage to fire the tube 90. Once this tube is fired, the current through the relay coil 92 is sustained until it is momentarily broken by the timing switch 72. Switches 71 and 72 close before the next sheet is lifted and remain closed until that sheet has been disposed of.

It will thus be noted that means have been provided for utilizing the usual automatic feeding operation to simultaneously gauge the individual sheets as they are fed. Furthermore, where the gauging means detects a sheet which is either too thin or too thick to be satisfactory, that sheet will be diverted from the ordinary conveying path. Such sheets may be either delivered to trays from which they may be removed, or they may be delivered to conveying systems which remove them to suitable receiving means.

The above description and illustrations represent a typical and the preferred form of the invention. However, numerous mechanical changes in minor details including variations in circuit arrangements may be made within the scope of the invention as defined in the following claims.

What we claim is:

1. In combination with a sheet feeder having a crossbar and means for presenting a pile of horizontal sheets of tinplate and the like in spaced arrangement below the cross-bar, means on the cross-bar for pneumatically lifting the uppermost sheet vertically from the pile for lateral movement away from the pile, a magnetically operating thickness gauge adjustably mounted on said cross-bar in the upward path of the sheet as it is lifted vertically, and means responsive to the gauge for separately sorting the sheets after they have been gauged.

2. In combination with a sheet feeder having a crossbar .and means for presenting a pile of horizontal sheets of tinplate and the like in spaced arrangement below the cross-bar, means on the cross-bar for pneumatically liftmg the uppermost sheet vertically from the pile for lateral movement away from the pile, a magnetically operating thickness gauge adjustably mounted on said cross-bar in the upward path of the sheet as it is lifted vertically, electromc means responsive to the gauge measurement, sheet sorting means and actuating means operated by the electron c means for actuating the sheet sorting means ac cording to the gauge measurement.

3. In combination with a sheet feeder having a crossbar and means for presenting a pile of horizontal sheets of tinplate and the like in spaced arrangement below the cross-bar, means on the cross-bar for pneumatically liftmg the uppermost sheet vertically from the pile for lateral movement away from the pile, a magnetically operating gauge for measuring sheet thickness adjustably mounted on the cross-bar in the upward path of the sheet as it is lifted vertically, means for comparing said measurement against the measurement of a standard sheet, sheet sorting means and means actuated by the said comparison for operating the sorting means.

4. In combination with a sheet feeder having a cross- 7 i 8 bar" and means for presenting a pile of horizontal sheets receiving means, and means responsive to said comparaof tinplate arid the like in spaced arrangement below the tive measurement for feeding the sheets to the approcross-bar, means on the cross-bar for pneumatically 1ift-- Pilate Tecelvlng meansing the uppermost sheet vertically from the pile for lateral movement away from the pile,'a magnetically operating 5 gauge for measuring sheet thickness adjustablymounted References Cited in the file of this patent UNITED STATES PATENTS ontliel crossbar in the. upward path of the sheet astit is 75,296,719 Looney Sept, 22, 1942 lifted vertically, means for comparing said measurernent 233 06111 Geiss Dec; 22, 1942 against the measurement of astand ar d sheet, a plurality- 2,312,357 O dquist Mar. 2, 1943 of sheet receiving means, fingers operated by the sheet 10 2,344,596 Carmina Q Mar. 21, 1944 feeder for directing the sheets selectively'to one of said 2,6 5,34 Diamond July 14, 1953 

1. IN COMBINATION WITH A SHEET FEEDER HAVING A CROSSBAR AND MEANS FOR PRESENTING A PILE OF HORIZONTAL SHEETS OF TINPLATE AND THE LIKE IN SPACED ARRANGEMENT BELOW THE CROSS-BAR, MEANS ON THE CROSS-BAR FOR PNEUMATICALLY LIFTING THE UPPERMOST SHEET VERTICALLY FROM THE PILE FOR LATERAL MOVEMENT AWAY FROM THE PILE, A MAGNETICALLY OPERATING THICKNESS GAUGE ADJUSTABLY MOUNTED ON SAID CROSS-BAR IN THE UPWARD PATH OF THE SHEET AS IT IS LIFTED VERTICALLY, AND MEANS RESPONSIVE TO THE GAUGE FOR SEPARATELY SORTING THE SHEETS AFTER THEY HAVE BEEN GAUGED. 